There are two possible solutions. One solution is to relabel the data entries with numerical values into words.
For instance, the data set contains numerical values specifying months and the days of the month as an integer, i.e. the month is indicated as a number 1, 2, . . . , 12 and the day of the month is indicated as a number 1, 2, . . . , 31. To avoid discretization of day and month the values can be relabeled into words: First, Second, and so on for days and January, February, and so on for months.
The other solution is to use the <ph -update> command on a HUGIN network file that contains variables representing day and month. That is, a model with two variables is created using the HUGIN GUI. One numbered variable with states 1, . . . , 12 representing the month and one numbered variable with states 1, . . . , 31 representing the day of the month are created. The model is store in a HUGIN network specification file. This file is given as an argument to <ph -update> command along with the initial data set.